COMPARISON OF THE RECOVERY AND HALF-LIFE OF A HIGH-PURITY FACTOR-IX CONCENTRATE WITH THOSE OF A FACTOR-IX COMPLEX CONCENTRATE

Background: Recovery and half-life estimations were carried out to com pare a high-purity factor IX concentrate with an established factor IX complex concentrate. Study Design and Methods:Two high:purity factor IX concentrates, which are identical except for the presence or absenc e of heparin (Immunine(hep-plus) and Immunine(hep-minus)), were evalua ted in two independent crossover studies using an intermediate-purity factor IX complex concentrate (Bebulin) as reference drug. Results: In the Immunine(hep-plus) crossover study (n = 27), Immunine(hep-plus) a nd Bebulin had, respectively, a recovery of 0.90 +/- 0.26 and 0.84 +/- 0.23 IU per dL per IU per; kg, a compartmental half-life of 17.11 +/- 6.18 and 15.94 +/- 4.69 hours, and an effective half-life of 16.51 +/ - 3.48 and 16.48 +/- 4.26 hours. In the Immunine(hep-minus) crossover study (n = 26), Immunine(hep-minus) and Bebulin had, respectively, a r ecovery of 0.92 +/- 0.31 and 1.02 +/- 0.36 IU per dL per IU per kg, a compartmental half-life of 17.42 +/- 5.60 and 18.77 +/- 6.27 hours, an d an effective half-life of 16.39 +/- 4.44 and 16.48 +/- 4.28 hours, E quivalence tests indicated that the recovery and half-life of Immunine , with or without heparin, are equivalent to those of Bebulin. Conclus ion: The equivalence in pharmacokinetics and bioavailability indicates that the dosage schedule for Immunine should be the same as or very s imilar to that of Bebulin. The high specific activity of the former, h owever, allows administration at lower volumes.